I don't think you actually HAVE to pass the chuunin exam to become a chuunin. And in fact lots of countries don't even participate in the exame. There were no Stone or Cloud or Mist ninjas in the chuunin exam and those are the other 3 major villages.

The "Chuunin exam" is only used by Konoha and it's allies to promote ninjas, and then only as a form of advertisement for the villages. But if the sound village wants to promote 4 of it's ninjas to chuunin, you can't really stop them.

Just like if Tsunade goes, "I'm just gonna promote Naruto because I feel like it" she can do that if she wants. She's hokage.


As far as the ANBU, they're just special forces. The ANBU can have both Chuunins and Jounins in them. Because as has been stated, ANBU is not a rank, it's just a special team designed for a special task. But those who aren't at leasts Chuunin probably won't become ANBU because there's a minimum amount of skill needed to be assigned to a special forces team like that.